Removing Old Exchange and installing a new one.

Hello

I currently have windows server 2012 installed as my Domain controller.

I was  practicing exchange 2010 on a win2k8 in my Hyper-V environment and decided i no longer need it so i just delete the machine.

Now i want to install a new exchange 2010 and want to completely delete the old one from AD but i can't because it was a DC.

If i install a new exchange 2010 in my domain will it just pick everything up with the setting from the old one or should i first remove the old exchange completely out of AD and start fresh?

thanks for all the help mates.